Bitumen Flex sealing tape
When bitumen aluminium tape is not enough
Flex sealing tape – up to 30% stretchable with special fleece
Bitumen flex sealing tape differs from bitumen aluminium tape in its carrier material: instead of a rigid aluminium top layer it has a special fleece that makes the tape stretchable in all directions by up to 30%. This sounds technical but has a simple consequence on site: it conforms to corners, curves and irregular transitions without wrinkling or tearing, and permanently bridges movement in joints.
Flex sealing tape 50 mm
For narrow movement joints, active cracks and tight connections. Bestseller in this category. EUR 8.20 / 10 m (EUR 0.82/m), tiered pricing from 6 rolls.
To 50 mm flex tape → Connections & valleys ★Flex sealing tape 100 mm
For chimney connections, valleys, roof light connections and wider transitions. Second most purchased. EUR 13.20 / 10 m (EUR 1.32/m).
To 100 mm flex tape → Wide transitions ★Flex sealing tape 150 mm
For wide wall connections, dormers and complex transitions with larger movement ranges. EUR 17.95 / 10 m (EUR 1.80/m).
To 150 mm flex tape →All widths compared
7 widths – from joints to wide wall connections
| Width | Typical application | Price / 10 m | Price/m |
|---|---|---|---|
| 50 mm ★ | Narrow movement joints, active cracks, tight corners | EUR 8.20 | EUR 0.82/m |
| 75 mm | Medium joints and connections | EUR 10.90 | EUR 1.09/m |
| 100 mm ★ | Chimneys, roof lights, valleys | EUR 13.20 | EUR 1.32/m |
| 150 mm ★ | Dormers, wide wall connections | EUR 17.95 | EUR 1.80/m |
| 200 mm ★ | Large chimney connections, wide valleys | EUR 22.95 | EUR 2.30/m |
| 250 mm | Large-area transitions, eave details | EUR 29.50 | EUR 2.95/m |
| 300 mm | Maximum coverage, large-area wall connections | EUR 34.80 | EUR 3.48/m |
★ Bestsellers. Tiered pricing: 50 mm from 6 rolls (down to EUR 0.79/m), 75 mm from 4 rolls, 100 mm from 3 rolls.
Typical application areas
Where flex tape shows its strength
Chimney connections
The transition between chimney and roof surface is geometrically complex – angles, curves, different building materials. Flex sealing tape conforms without tearing. For chimneys, 100 to 200 mm width is recommended depending on the connection geometry.
Valleys and dormers
At valleys and dormers, roof surfaces meet at acute angles. Flex sealing tape lies into the corner without wrinkling and seals the entire connection length – even if the substrate is slightly uneven.
Refurbishments with active cracks
During refurbishment, cracks can still change through settlement and temperature movement. The flex tape absorbs these movements with its 30% stretchability – a rigid aluminium tape would crack at such points over time.
Practical tip for installation
30% stretch – but don't overstretch
The 30% stretchability is a maximum value – the tape should not be stretched to this limit as it will then be under tension and can detach. Apply the tape loosely, conform corners and valleys by gently pressing rather than pulling. For difficult geometries, make cuts and overlap. Keep the substrate clean and dry for lasting adhesion.
Frequently asked questions
Frequently asked questions about bitumen flex sealing tape
What is the difference between flex sealing tape and bitumen aluminium tape?
Bitumen aluminium tape has a rigid aluminium top layer – dimensionally stable and good for flat surfaces but does not conform flexibly. Bitumen flex sealing tape has a stretchable special fleece carrier – stretches up to 30% and conforms to corners, curves and irregular geometries. For straight surfaces aluminium tape is often sufficient; for complex connections flex sealing tape is the better choice.
Can flex sealing tape be installed around corners and into valleys?
Yes – that is its central advantage. The stretchable special fleece allows the tape to be applied around internal and external corners and into valleys without wrinkling. At acute angles, press the tape gently rather than pulling to stretch, or make cuts and overlap.
Can flex sealing tape permanently bridge active cracks?
Yes. The up to 30% stretchability allows it to absorb movement in joints and cracks without tearing. For cracks that seasonally open and close through temperature movement, flex sealing tape is significantly superior to rigid aluminium tape.
Which width for chimney connections?
The tape must have at least 5 cm contact on both sides of the connection. For narrow chimneys 100 mm is often sufficient; for wide chimneys or connections where plastering is planned, 150 to 200 mm is recommended.
Is flex sealing tape weather-resistant?
Yes. Elastomer bitumen is permanently UV and weather resistant. The special fleece provides additional mechanical stability. The tape can be painted over for permanently visible areas.
Permanently seal movement joints and demanding connections
Choose the right width now.
Up to 30% stretchable – self-adhesive, immediately watertight, in 7 widths from 50 to 300 mm.